mercruiser wont rev out

[eoin1981]

hi posting this for a mate hes got a 1.7 diesel 120 mercruiser engine but it wont rev past 3000 revs he got a compression test done and all seems fine maybe somebody here could point us in the right direction

[kubcat]

A quick Google says it should rev to 4400rpm.

There are many factors to look at.

Did this boat ever reach these revs? If it didn't, then maybe it has the wrong prop. If it did, what has changed? Is there growth on the hull? Is the prop or drive leg dinged? Is there a lot if extra weight in the boat? etc.

Give us some more information including the type of boat, hours on the engine and some general history as a start.